Methyltin Chlorides (5526)
METHYLTIN CHLORIDES Formula: Table 1
MW: Table 1
METHOD: 5526, Issue 1
CAS: Table 1
RTECS: Table 1
EVALUATION: FULL
Issue 1: 15 March 2003
PROPERTIES: See Table 1
OSHA : See Table 1 NIOSH: See Table 1 ACGIH: See Table 1 SYNONYMS:
5526
Methyltin Trichloride: Trichloromethylstannane, Monomethyltin trichloride Dimethyltin Dichloride: Dichlorodimethylstannane, Dichlorodimethyltin Trimethyltin Chloride: Chlorotrimethylstannane, Chlorotrimethyltin, Trimethylstannyl chloride SAMPLING
SAMPLER:
FILTER + SORBENT TUBE (OVS Tube: 13-mm glass fiber filter; XAD-2, 270/140 mg)
FLOW RATE:
0.25 to 1 L/min
VOL -MIN: -MAX:
15L 75L
SHIPMENT:
Ship assembled sampler cold
SAMPLE STABILITY:
14 days @ 4 °C
FIELD BLANKS:
2 to 10 field blanks per set
ACCURACY
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FPD (tinspecific filter)
ANALYTE:
Sodium tetraethylborate derivatives of the analytes
DESORPTION:
2 mL 1% acetic acid in acetonitrile
INJECTION VOLUME:
1 :L
TEMPERATURE -INJECTION: -DETECTOR: -COLUMN:
Cool-on-column 250 °C 50 °C (3min), 12°C/min to 200°C (1min)
CARRIER GAS:
He, 6 mL/min
COLUMN:
Capillary, fused silica, 30m x 0.53mm ID, 1.5-:m film, 5% phenyl, 95% methyl silicone, DB-5 or equivalent.
RANGE STUDIED:
Table 2
BIAS:
Table 2
CALIBRATION:
Analytes in hexane
OVERALL PRECISION (Ö r T ):
Table 2
RANGE:
0.01 to 15 :g/sample (as tin) [1]
ACCURACY:
Table 2
ESTIMATED LOD: 0.01 :g [1] PRECISION ( þ r ):
0.065 [1]
APPLICABILITY: This method was developed for air monitoring of methyltin chlorides.[1]
INTERFERENCES: None were identified.
OTHER METHODS: NMAM 5504 is another method for the measurement of organotin compounds using a filter with a sorbent tube for collection and HPLC/AA for analysis [3].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYLTIN CHLORIDES: METHOD 5526, Issue 1, dated 15 March 2003 - Page 2 of 5 EQUIPMENT:
REAGENTS: 1. 2. 3. 4. 5. 6. 7. 8. 9.
Acetic Acid, 99 +% .* Aceton itrile, HPL C grade .* Dieth yl Ether, 99+% .* Hex ane, H PLC grade *. Methyltin Trichloride, 97%. Dimethyltin Dichloride, 97%. Trimethyltin Chloride. 1% acetic acid in acetonitrile solution, (v/v). Sodium tetraethyl borate.* NOTE: Pu rity of sodium tetraethyl borate is critical. It should appear as a fine white powder. Clumping or yellowing indicates that the compound m ust be replaced. 10. Sodium Acetate - Acetic Acid Buffer, pH 4.0 ± 0.2. Com mercially available from Fisher Scientific. 11. Derivatizing Solution: Prepare a solution containing 1% (w/v) of sodium tetraethylborate in diethyl ether. Prepare the solution fresh daily, preferably im m ediate ly before use. 12. Calibration Stock Solution: Prepare a stock calibra tion so lution by accurate ly weighing (to ± 0.1 m g) about 0.1 g each of m eth yltin trichloride, dimethyltin dichloride and trim eth yltin chloride into a 50 m l volum etric flask . Dilute to volum e with 1% acetic acid in acetonitrile. The stock solution contains about 1000 :g/m l (as tin) of eac h co m pon ent. Stored in a freezer, this solution remains stable for several weeks.
1.
Sampler: OSHA Versatile Sampler (OVS tube ), 13-m m OD inlet, 6-m m OD outlet. Front section contains 270 mg 20/60 mesh XAD -2 sorbent held in place by an 11-m m diameter glass fiber filter and Teflon® ring, separated from the back section of 140 mg XAD-2 sorbent by a short plug of polyureth ane fo am . The back sectio n is held in place with a plug o f polyure than e foa m . The tube is available comm ercially from SKC, Inc. (c at. #226-3 0-16 ) and Sup elco, Inc. (cat.
- OR BO -49P).
2. Personal sa m pling pum p: 0.1 to 1 L/m in with flexible and inert connecting tubing. 3. Gas chromatograph equipped with a cool oncolum n injec tion po rt, autom ated injecto r, DB-5 capillary c olum n, flam e-photo m etric detector (FPD) with a tin-specific filter (610 nm), and data collection system or equivalent (page 552 6-1). 4. Balance capable of weighing to ±0.1 mg. 5. Mec hanical shake r. 6. Vials, 10-mL, with PTFE-lined screwcaps. 7. Transfer pipettes or eyedroppers. 8. GC autosampler vials with PTFE-lined caps. 9. 5-mL,10-mL and 50-mL volumetric flasks. 10. Pipettes capable of accurately delivering 10
- L and 1.0 and 2.0 mL.
11. Refrigerant packs for shipping.
- See SPECIAL PRECAUTIONS
SPECIAL PRECAUTIONS: Concentrated acetic acid is corrosive and an irritant. Sodium Tetraethylborate is sensitive to air and m oisture. This chem ical should be stored and h andled unde r a nitrogen a tm osp here . Ace tonitrile, diethyl ether, and h exa ne a re all flam m able. W ear a ppro priate protective clothing and work with these compounds in a well ventilated hood. SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Uncap the sorbent tube immed iately before sampling and connect to a personal sampling pum p with flexible tubing. 3. Sa m ple at an accurately k nown flow rate betw een 0.25 L/m in fo r full shift sam pling and 1 L/m in for 15 minutes samples (STEL) for a maximum of 75 L. 4. Cap the samplers. Pack securely for shipment with cold refrigerant packs. NOTE: After receipt at the laboratory, samples should be stored at 4°C and analyze within 14 days of collection.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYLTIN CHLORIDES: METHOD 5526, Issue 1, dated 15 March 2003 - Page 3 of 5 SAMPLE PREPARATION: 5. Rem ove the retaining ring from the sorbent tube and discard. Transfer the glass fiber filter and the m ain resin bed to a 10-m L sam ple vial. 6. Rem ove and discard the foam plug that separates the two resin sections in the sorbent tube. Transfer the back up res in bed to a second 10-m L sam ple vial. 7. Into each vial, add 2 ml of 1% acetic acid in acetonitrile to desorb the m ethyltin chlorides . Put the vials on a mechanical shaker for 30 minutes. 8. Into each vial, add 2 ml of pH 4 buffer and 1 ml of derivatizing solution. Place the vials on the mechanical shaker for 15 minutes. 9. Extract the solution with three 1 ml portions of hexane. Com bine the hexane fractions in a 5 m l volum etric flask and dilute to volume with hexane.
CALIBRATION AND QUALITY CONTRO L: 10. Ca librate daily with at leas t six wo rking standa rds over the ra nge of interest. a. Ac curately pipette 10 :l of the c alibration stoc k solution into a vial that contains 5 mL of 1 % acetic acid in ace tonitrile. De rivatize like a sam ple following steps 7 throug h 9. b. Serially dilute this standard derivatized solution with hexane to produce solutions over the range of 0.2 to 0.02 :g/mL (as tin) of each methyltin chloride. c. Transfer to gc autosampler vials with PTFE-lined caps. d. Analyze together with samp les and blanks (steps 12 through 14). e. Prepare calibra tion gra ph (p eak area s vs. :g tin for eac h m ethyltin chloride). 11. De termine desorption efficiency (DE) at least once for each lot of O VS tubes used for sam pling in the calibration range (step 10). Prepare three samplers at each of six levels plus three media blanks. a. Transfer the front so rbent se ctio n of the O VS sam pler to a 4m L vial. b. Inject a known volume of calibration stock solution, or serial dilution, directly onto the front sorbent bed of ea ch O VS tube. c. Ca p vial an d allow spik ed s orbe nt bed to stand overnight. d. Deso rb (steps 7 through 9 ) and analyze together with standards and b lanks (steps 1 3 through 15). e. Prepare a gra ph o f DE vs. :g for eac h m ethyltin chloride re covered . 12. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and DE graphs are in control.
MEASUREMENT: 13. Set gas chromatograph according to manufacturer’s recomm endations and to conditions given on page 552 6-1. 14. Inject a 1-:L sa m ple aliqu ot m anu ally using solve nt flush technique o r with an au tosa m pler. NOTE: If peak area is above the linear range of the working standards, dilute with hexane, reanalyze, and apply the appropriate dilution factor in the calculations. 15. Mea sure the area s of th e pe aks of th e m ethyltin chlorides . A sample chromatogram is shown in Figure 1.
CALCULATIONS: 16. Determine the m ass , :g (corrected for DE), for each m ethyltin chloride found in the sam ple front (W f) and back (W b) sorbent sections, and in the averag e m edia blank front (B f) and back (B b)sorbent sections. NO TE: If W b > W f/10, report breakthrough and possible sample loss. 17. Calculate conce ntration, C, of each m ethyltin chloride in the air volume sa m pled, V (L): NO TE : :g/L / m g/m 3
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYLTIN CHLORIDES: METHOD 5526, Issue 1, dated 15 March 2003 - Page 4 of 5 EVALUATION OF METHOD: This method, developed to collect air samples and analyze the methyltin chlorides, was adapted from existing methodology for measuring organotin compounds in air [3,4]. Reference 1 details the validation of this method for sampling and quantifying of trimethyltin chloride, dimethyltin dichloride and methyltin trichloride in air. The validated method was needed to provide air monitoring capabilities during methyltin chloride and stabilizer production. Table 2 lists the results of the validation experiments which followed the guidelines established by NIOSH [2]. However, fewer replicates and concentration levels were used than recomm ended. This method m et the NIOSH criteria for accuracy, bias and sample stability. The recom m ended sampling conditions are 250 ml/min for 5.5 hours maximum for time-weighted average (TW A) sampling and 1000 ml/min for 20 minutes maximum for short-term exposure limit (STEL) sampling.
REFERENCES: [1] Yoder RE [2000]. Validation of a Method for the Collection and Quantification of M eth yltin C hlorides in the Air. Philadelphia, PA: Atofina Chem icals. Unpublished. [2] NIOSH [1995]. Guidelines for Air Sampling and Analytical Method Development. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 95-117. [3] NIOSH [1994]. Organotin Co m pounds (as Sn): M eth od 5504. In: Eller PM, Cassinelli ME, eds. NIOSH Manual of Analytical Methods, 4th Ed. Cincinnati, OH: U.S. Department of Health and Human Se rvic es,Pu blic He alth Servic e, C enters for Dis ease Co ntrol and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113. [4] Shangwei H [1997]. Development of a Method for the Sampling and Analysis of Dimethyltin Dichloride and Trimethyltin Chloride [Dissertation]. New Orleans, LA: Tulane University, Department of Environmental Sciences, School of Public Health and Tropical Medicine.
METHOD WRITTEN BY: R.E. Yoder, C. Boraiko, Atofina Chemicals; P.F. O’Connor, NIOSH/DART. TABLE 1. GENERAL INFORMATION Analyte
OSHA PELa (mg/m3)
NIOSH RELb (mg/m3)
ACGIH TLVc (mg/m3)
WH858550 Colorless Crystals MP 48-51°C BP 171°C
0.1
0.1
0.1 0.2 STEL (skin)
753-73-1
WH7245000 Colorless Crystals MP 103-105°C BP 188-190°C
0.1
0.1
0.1 0.2 STEL (skin)
1066-45-1
WH685000 Colorless Crystals MP 37-39°C BP154 °C
0.1
0.1
0.1 0.2 STEL (skin)
Formula
Mol. Wt.
CAS#
Methyltin trichloride
CH3Cl3Sn
240.04
993-16-8
Dimethyltin dichloride
C2H6Cl2Sn
219.67
Trimethyltin chloride
C3H9ClSn
199.25
RTECS#
Properties
a
- OSH A PEL is mea sured as the am ount of Tin (Sn) for orga notin com pounds in air. - NIO SH RE L is m eas ured as the am oun t of T in (Sn ) for organ otin co m pou nds in air. c - AC GIH TL V is m eas ured as the am oun t of T in (Sn ) for organ otin co m pou nds in air.
b
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition METHYLTIN CHLORIDES: METHOD 5526, Issue 1, dated 15 March 2003 - Page 5 of 5 TABLE 2. METHOD EVALUATION [1] Range Studied
Bias (%)
Precision(S rT) (%)
Accuracy (%)
Trimethyltin chloride
0.46 - 9.29 :g/sample (tin)
0.3
5.2
11
Dim eth yltin dichloride
0.42 - 9.17 :g/sample (tin)
-2.5
5.8
12
Methyltin chloride
0.07 - 10.48 :g/sample (tin)
-5.2
7.6
16
Figure 1:
Sample Chromatogram
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition